重组人促红细胞生成素聚乙二醇修饰及纯化研究

目的　研究重组人促红细胞生成素 (rhEPO)聚乙二醇修饰条件及纯化方法。方法　用SDS PAGE分析不同反应条件对产物成分的影响 ;用红细胞压积法测定各组分的体内生物学活性 ;用分子筛柱层析进行纯化。结果　rhEPO的修饰度随蛋白浓度、蛋白与PEG2 NHS活性酯质量比的增加而提高 ,体内生物学活性随修饰度增加而降低 ,分子筛柱层析纯化效果好。结论　确立了rhEPO聚乙二醇化的影响因素及纯化方法     

Physiochemical and biological properties of modified collagen sponge from porcine skin

The aim of the present study was to compare one-step method to EDC/NHS crosslinking (EDC/NHS group) and one-step simultaneous method to EDC/NHS crosslinking and heparin immobilization (EDC/NHS- Heparin group) in improving physiochemical and biological properties of native collagen sponge (Control group). Modified collagen sponge overcome the disadvantages of native collagen sponge. IR spectra suggest the change of the functional groups. DSC data indicate that the stability of caloric transformation in EDC/NHS group is slightly higher than that of EDC/NHS-Heparin group. The crosslinking degree, stability against enzymes, stability in morphologically and biomechanical properties of EDC/NHS-Heparin group are higher than those of EDC/NHS group, whereas, the water-binding capacity in EDC/NHS-Heparin group is lower than that of EDC/NHS group. HUVECs in EDC/NHS-Heparin group scaffold proliferate fast, migrate well and distribute uniformly. One-step simultaneous method gains the better effects in above aspects, heparinized collagen matrices increase in angiogenic potential and suit for defect repairing and tissue engineering. Funded by the National Natural Science Foundation of China (10832012) and the Natural Science Foudation of Tianjin city(08JCYBJC03400)     

Polyacrylonitrile-based nanofibers—A state-of-the-art review

Polyacrylonitrile (PAN), a well-known polymer with good stability and mechanical properties, has been widely used in producing carbon nanofibers (CNFs) as these have attracted much recent attention due to their excellent characteristics, such as spinnability, environmentally benign nature and commercial viability. Among the various precursors to produce CNFs, PAN has been extensively studied due to its high carbon yield and flexibility for tailoring the structure of the final CNFs as well as the ease of obtaining stabilized products due to the formation of a ladder structure via nitrile polymerization. In view of this, they have applications in areas such as electronics, tissue engineering, membrane filtration and high performance composites. This review presents various combinations of PAN and PAN-based precursors in producing CNFs from the PAN homopolymer or its modified precursors, copolymers, blends and various composites. Various modifications of PAN and their future prospects in different scientific and technological disciplines are addressed.     

Construction of an electrochemical probe for on chip type flow immunoassay

Miniaturized immunosensors, that combine the analytical power of microfluidic devices with the high specificity of biomolecules, have been intensively studied for clinical analyses, environmental immunoassays and biochemical studies. Protein A has the ability to bind Fc-binding site of immunoglobulin G (IgG), and can be used as the detection probe in immunoassays. Ferrocenecarboaldehyde (Fc-CHO) was labeled to protein A as an electrochemical probe for on chip type amperometric flow immunoassay. When labeling Fc-CHO onto protein A via formation of Schiff-base and its reduction, mean number of nine Fc-CHO labeled to individual protein A molecules. Protein A labeled with Fc-CHO exhibited reversible redox properties of ferrocene in cyclic voltammograms and its peak currents increased with number of labeled ferrocenes. The current response of protein A labeled with Fc-CHO well correlated with its concentration when applying 390 V versus Ag/AgCl. Protein A labeled with Fc-CHO showed sufficient electrochemical properties that are useful in a miniaturized electrochemical immunoassays.     

The Use of a Formalised Risk Model in NHS Information System Development

Information systems (IS) and technology are used extensively throughout the National Health Service (NHS), and the 1998 national information strategy, ‘Information for Health’, sets out how the NHS will be developing and implementing IS to support patient care within the next decade. This new IS initiative is set against a mixed record of success of IS projects in the NHS, with a number of high-profile failures. This paper highlights the need to consider the ‘organisational issues’ involved in systems implementation to avoid failures. It goes on to advocate the use of a process-oriented and organisation studies-based model for risk analysis and management for use in NHS IS projects. Two famous NHS case studies are used to validate the model. It is concluded that there is a real need in the NHS for tools to better control the inherent risks involved in IS development and implementation. Ultimately, the success of IS projects in the NHS is crucial if they want to best utilise clinical and patient information, with the overall aim of improving the efficiency and standard of the nation’s health care.     

Specific control of cell–material interactions: Targeting cell receptors using ligand-functionalized polymer substrates

Cells respond to their environment in complex and sometimes poorly understood ways. Protein, peptide and synthetic peptidomimetic ligands may all be used to stimulate cells via receptor signaling, using interactions that are often highly specific. Polymer substrates that present these ligands provide a promising way to control cell development, both for applications in biotechnology and for fundamental studies of cell biology. Here we review a large range of techniques that have been employed to create and characterize ligand-functionalized substrates, with a particular focus on techniques that allow specific and consistent stimulation.     

Polymer vectors via controlled/living radical polymerization for gene delivery

The design of efficient gene delivery vectors is a challenging task in gene therapy. Recent progress in living/controlled radical polymerizations (LRPs), in particular atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization providing a means for the design and synthesis of new polymeric gene vectors with well-defined compositions, architectures and functionalities is reviewed here. Polymeric gene vectors with different architectures, including homopolymers, block copolymers, graft copolymers, and star-shaped polymers, are conveniently prepared via ATRP and RAFT polymerization. The corresponding synthesis strategies are described in detail. The recent research activities indicate that ATRP and RAFT polymerization have become essential tools for the design and synthesis of advanced, noble and novel gene carriers.